biology ppt class 11 on androecium unit 1

2. INTRODUCTION
WHAT IS A FLOWER
• The seed-bearing part of a plant, consisting of reproductive
organs (stamens and carpels) that are typically surrounded
by a brightly coloured corolla (petals) and a green calyx
(sepals).
REPRODUCTIVE PARTS OF FLOWER
• Androecium
• gynoecium

3. ANDROECIUM(MALE REPRODUCTIVE
PART)
• It is composed of stamens.
• Stamen consists of anther , filament and stalk.
Anther
• Usually bilobed and each lobe has two chambers ,the pollen sacs
where pollen grains are produced .
Stamens
• Epipetalous:- attached to petals.
• Epiphyllous:-attached to perianth .eg:lily.
• Monoadelphous:-stamens united to one bunch or bundle.eg:china
rose
• Diadelphous:-stamens united to two or more bundles. Eg:pea.
• Polyadelphous:-stamens united to two or more bundles .eg:citrus .

4. GYNOECIUM(FEMALE
REPRODUCTIVE PART)
• It is composed of one or more carpels .
• It consists of three parts stigma ,style ,ovary.
• Ovary is enlarged basal part to which lies the elongated
tube style.
• Ovary bears one or more ovules attached to the placenta .
• Apocarpous:- carpels are free.eg:-lotus and rose
• Syncarpous:-carpels are fused.eg:-mustard and tomato
• Stigma is usually at tip of the style it is receptive surface of
pollen grain.
• Style connects ovary to stigma.

5. PLACENTATION
• Placentation: arrangement of ovules in ovary.
• Placentation are of 6 types:-
• Marginal :-placenta forms a ridge along the ventral suture
of ovary and ovules are borne on this ridge forming two
rows eg:pea
• Axile:-ovules attached to placenta in multilocular ovary eg:
rose
• Parietal:-ovule develops on inner wall of ovary.
• Free central:-ovules borne on central axis, septa absent eg
Dianthus
• Basal:-placenta develops at base of ovary, single ovule
attached to it.eg sunflower .

7. FRUIT
• A characteristics feature of flowering plants
• Fruit formed without fertilization of ovary is
parthenocarpic.
• Structure of fruit
• It consists of wall or pericarp which maybe dry or fleshy
• It is differentiated into outer epicarp , middle mesocarp
and the inner mesocarp.

8. SEED
• What is seed??
The unit of reproduction of a flowering plant, capable of
developing into another such plant.
• Structure of seed
• Outer most covering is a seed coat
• Seed coat has two layers the outer testa ,inner tegmen.
• A scar on seed coat through which developing seeds are
attached to fruit is hilum . Small pore above hilium is
micropyle.
• Radicle: the part of a plant embryo that develops into the
primary root.
• Plumule:-the immature shoot or stem of an embryo plant

9. STRUCTURE OF DICOTYLEDONOUS SEED
• Seed coat consists of two cotyledons which contain food material
and are fleshy and embryonal axis .
• Radicle and plumule are present at the end of embryonal axis .
• On basis of food storing tissue seeds are of two types:-
• Endosperm seed: -developing seed in which endosperm is present
and develops as a result of double fertilization.
• Non-endospermous seed :-mature seeds in which endosperm is
absent.eg bean , gram and pea

10. STRUCTURE OF MONOCOTYLEDENOUS
SEED
• They are endospermic except orchids which are non-
endospermic.
• Endosperm is bulky and stores food.
• Seed coat is membranous and fused with fruit wall

12. STRUCTURE
• Outer covering of endosperm separates the embryo by a
proteinous layer call aleurone layer .
• The embryo is small and it is situated in depression at
one end of endosperm.
• Embryo consists of large & shield shaped cotyledon
known as scutellum.
• Embryo consists of short axis with plumule and radicle
• Plumule and radicle are enclosed in shealth called
coleoptile and coleorhiza

13. Summing up
• Flower:-seed bearing part of plant.
• Androecium :-female reproductive whorl of a
flower consists filaments,stalk,anther
• Gyonecium :-male reproductive part consists of
anther style stigma
• Placentation :-arrangements of ovules in ovary. It
is classified into parietal,marginal,axile ,free
central, basal.
• Seed :-unit of reproduction
• Monocotyledonous seed:-consists of one
cotyledon
• Dicotyledonous:-consists of 2 cotyledons